It is standard in electrophotographic printer or copier devices to fix the toner-coated recording medium in a thermal fixing station. Such thermal fixing stations generally contain electrically heated fixing drums with applicable pressure rollers that can be pivoted in and out. For fixing, the recording medium is conducted past between the fixing drum and the pressure roller. The toner is fixed on the recording medium due to the application of heat from the side of the fixing drum. Since the toner must be brought to melting temperature during the short contacting distance of the recording medium with the fixing drum, a high heating capacity on the part of the fixing drum is necessary. For this purpose it is standard to install halogen radiators having a high heating capacity in the hollow fixing drum. Both the halogen radiators in the fixing drum as well as the fixing drum itself are subject to wear, so that it is necessary from time to time to replace the halogen radiators and the fixing drum.
In order to be able to replace the fixing drum in its hot condition as well, PCT WO 91/09 351 discloses that the fixing drum be seated in bearing flanges, whereby the one bearing flange is permanently secured and the other bearing flange is releasably secured in the device. The releasable bearing flange comprises holder elements for the fixing drum as well as a gripping member with which the bearing flange together with the fixing drum appended thereto can be removed from the fixing station. The releasable bearing flange is then separated from the worn fixing drum and is put in place on a new, replacement fixing drum which is then introduced into the fixing station via the bearing flange.
It has proven disadvantageous given this known apparatus to introduce the cold, new fixing drum into the fixing station via the releasable bearing flange since this can be done only after a cool-down time. Due to the relatively high thermal capacity of the fixing station, cools only slowly after shut-off, so that the bearing flange remaining in the fixing station is more greatly expanded due to the heat than the new, cold fixing drum. It is thus not possible during the cool-down time to put the new fixing drum in place on the bearing flange situated in the fixing station. Smaller problems arise in conjunction with the releasable bearing flange when put in place onto the new fixing drum. Here, too, it is necessary to allow the releasable bearing flange to cool.